Find out why professional services organisations are now looking at SIP trunking as an ISDN replacement and what the benefits are…

The ISDN standard was set in the late 1980s, during this era:
  • The worldwide web was just being invented
  • Mobile telephony was just finding its feet – and still analogue
  • Urgent business documents were often sent by fax
Since the launch of ISDN, many changes have taken place in the business world:
  • Remote working, flexible working and hot-desking have exploded
  • Many employees use both mobile and fixed-line telephony services during the workday
  • There has been increased focus on service, efficiency, business continuity and disaster recovery
  • IP-based services are commonly used by many organisations
In many ways, still using ISDN is like driving a classic sports car:
  • The car represented cutting-edge technology when it was launched
  • These days it’s not as efficient as its modern counterparts
  • The cost to keep the old model running is higher than a modern alternative
  • Reliability is a worry and issues can take days to resolve
  • Although a classic, sticking with the old model may no longer meet your basic needs
At this point, you’d consider upgrading to a newer model that is fit for purpose. Here’s why you should do the same if your business is still relying on ISDN:
  • ISDN lacks the agility needed to meet the needs of today’s fast-moving consumers
  • The management of multiple offices can be time-consuming, maintaining consistency of service across offices is often difficult
  • Scalability is slow and often expensive
  • ISDN-based telephony systems often require substantial capex investment
  • Disaster Recovery is slow
  • It can’t be combined with modern technologies like Ethernet to enhance voice services
Many professional services organisations are now opting for ISDN replacement services in order to drive efficiencies into their business in the face of its declining popularity:
  • In 2015, 3.1 million ISDN channels were used by UK business
  • In 2018, 2.3 million ISDN channels were used by UK business

Source: Ofcom: The Communications Market 2019

Next-generation technology SIP trunking is fast becoming the ISDN replacement solution of choice, as it can bring many benefits to your business, including:
  • Improved service features for greater efficiency gains
  • Increased flexibility to meet the changing needs of your workforce
  • Improved scalability to help drive business growth
  • Enhanced quality of service for customers
  • Improved resilience with built-in disaster recovery provisions
  • Reduced cost with significant savings to be made on call costs and line rental
  • Increased visibility of performance metrics to improve productivity and overall business performance

Technologies like SIP trunking offer a more flexible, cost-effective telecoms solution for your organisation to help you achieve your business goals. That is why it’s time to add ISDN replacement to your business agenda.


  • Carry out an audit of your telecoms system – when was the last time you looked to upgrade?
  • Find out how much your ISDN lines and on-site PBX system is costing you – how much could you save?
  • How resilient is your existing telecoms provision – how much could downtime cost your business?